<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .content{
            background-color: white;
            color: black;
            transition: background-color 1s;
        }

        #modeCheckBox{
            display: none;
        }

      #modeCheckBox:checked + .content{
          background-color: black;
          color: white;
          transition: all 1s;
      }

        #modeBtn{
            font-size: 2rem;
            float: right;
        }
    </style>
</head>
<body>
<input id="modeCheckBox" type="checkbox">
<div class="content">
    <header>
<!--思考：如何改变label的值（使用伪元素）-->
        <label id="modeBtn" for="modeCheckBox">切换</label>
        <h1>深夜食堂</h1>
    </header>
    <main>
        <p>hhhhh</p>
    </main>
</div>
</body>
</html>